1. Field of the Invention
The present invention relates to an improvement in an incinerating furnace utilizing mineral particles as a hearth bed, particularly to an improvement in removing used hearth particles and combustion remainder from the incinerating furnace.
2. Prior Art
It is known to use an incinerating furnace having a hearth bed consisting of mineral particles for incinerating plastic wastes which have a high calorific value and emit corrosive gases.
There are two types of incinerating furnaces having a hearth consisting of mineral particles. One is a fixed hearth and the other is a movable hearth. In the movable hearth furnaces the used hearth particles are taken out by a belt conveyer, by a rotating cylinder or by a rotating gear.
Incinerating furnaces of this kind are disclosed in Japanese Patent specification Sho No. 51-3139 (Kokoku No. 76-3139), Sho No. 52-21832 (Kokoku No. 77-21832) and Sho No. 56-685 (Kokoku No. 81-685), of which the hearths, consisting of mineral particles, are taken out by a belt conveyer disposed in the combustion chamber, Japanese laid open Sho No. 58-10831 (Kokai No. 83-10318), of which the hearth consisting of mineral particles is taken out by a rotary drum, and Japanese laid open Sho No. 63-217127 (Kokai No. 88-217127), of which the hearth consisting of mineral particles is taken out by a rotary gear.
Recently the need to incinerate used plastic equipment, such as plastic disposable injectors packed in a large plastic bag in incinerating furnaces of this kind has grown.
After the incineration of materials to be incinerated, for example, plastic wastes, a combustion remainder of large dimension often remains in combustion chambers of the incinerating furnace. They are very difficult remove from the incinerating furnace because the size of the outlet of the combustion remainder is fixed and generally is not large enough for allowing their removal.